Steps to take when ex is violating visitation rights

My ex-wife is violating my rights to visitation to my daughter.  We agreed on the Judge Brown Visitation standards when we went to court.  I was also hit with a huge child support payment of $540 a month when I only make $11 an hour.   I was forced to move in with my girlfriend to keep a roof over my head because you cannot survive on $800 a month.  Because I moved in with my girlfriend, she will not let my daughter stay with us overnight.  She drops her off in the morning, usually 2-3 hours late, and picks her up around 9PM.  My girlfriend and I have no intention of getting married, but we have been together for 3 years now.  So it is not like I am bringing random women into my daughters life.   We live in Simpsonville, SC.  Recently she decided to move to Laurens County, I am assuming with her boyfriend since that is where he is from.  By the visitation standard, it is her responsibility to bring her back to the original place of living for me to pick her up if she moves more than 15 miles away.  Well she moved over 30 miles away, and is telling me I have to drive to Laurens to pick her up, or forfeit my visitation for the weekend.  My car is in need of new brakes and is not safe to be driving long distances. On top of that, she refuses to give me any of the documents I request.  Medical records from when she goes to the doctor, social security card, birth certificate (all things I need for forms at my job in the civilian world and my Army Reserve records).  I cannot even get her to provide me with proof that she is still going to daycare, which is 50% of my child support payment.   What is the best course of action I need to take to remedy this situation.  It almost seems like we are going to have to go back to court to settle this because 18 hours a month with my daughter just isn't enough, and she is not willing to do anything to change that.